The Food and Drug Administration approved a controversial new form of emergency contraception Friday that can prevent a pregnancy as many as five days after sex.

The decision to allow the sale of the pill, which will be marketed under the brand name “ella,” was welcomed by family-planning proponents as a crucial new option to prevent unwanted pregnancies. But critics condemned the decision, arguing that it was misleading to approve ella as a contraceptive because the drug could also be used to induce an abortion.

Ella can cut the chances of becoming pregnant by about two-thirds for at least 120 hours after a contraceptive failure or unprotected sex, studies have shown. The only other emergency contraceptive on the market, the so-called morning-after pill sold as Plan B, is significantly less effective, becomes less effectual with each passing day and will not work after 72 hours.